I could perhaps see a charitable interpretation if the author of the blog post (Guzey) did not accuse the author of the book (Walker) of "deliberate data manipulation", gave the opportunity to the target of the accusation to explain himself, did not misrepresent himself as a "researcher" (pointing to his blog posts as examples of his "research"), did not link to a friend's blog post for "UC Berkeley’s official response", etc, etc.

The author of the blog post is not leaving a lot of room for charitable interpretations.

But in any case, what charitable interpretation do you propose?